package ch_01;

 public class VariableAndDataTy {
     /*public static void main(String[] args) {
         String name = "张三";

     }*/
     public static void main(String[] args) {
         //定义一个常量
         final  double I = 3.15;
         int radius = 6;
         double area1 = I*Math.pow(radius,2); //Math.pow 封装 R的二次方方法
         double area2 = I*radius*radius;


         System.out.println("圆的面积"+area1);
         System.out.println("面积"+area2);


     }
 }


